Clutch fan conversion on a 55

[EmTee]

I have a schematic for an active noise cancellation system that I found in the September 1968 issue of Popular Science.  It involves modifications to a 1962 Cadillac Wonderbar radio... 

[KAD36]

6 hours ago, Ttotired said:

You know, with the 200,000 words already posted on this subject, has anyone thought that the best thing to do is fix the actual problem instead of theorizing on 50 band aid fixes?

Well, we certainly won't beat the Girls on Buicks thread

 

So.. here are the results of some testing this weekend.  It was 75 outside and I found if the car was in the garage idling (with the door open of course) with the front of the car close to the wall so that the air going into radiator was heated by the engine, in incoming air outside the grill was measured at 93 degrees.

 

I took measurements with an el-cheapo-deluxe Harbor Freight infrared thermometer, which isn't very trustworthy but good enough for Govt purposes.  Measurements were at the top of the thermostat housing holding the thermometer about 2 inches from the housing.  Standard duty clutch and 6 blade 18 inch fan. 

 

After stabilizing on N on the temp gauge, which is about 180 on my car, and starting a timer 25 minutes of idling at 500 rpm in drive got this result:

 

 

This is what 235 deg looks like. This same situation happened in bumper to bumper traffic in Allentown just after getting off the exit after a few hours of 65-70 mph expressway driving, in the center of a 3 lane road with the traffic light way off in the distance and nowhere to go or an easy way to get to the side of the road.  No amount of revving the engine with the 4 blade factory stock fan would bring the temp down and I couldn't tell if racing the engine was making it worse or better. This would certainly not support an AC equipped car.  This is what I'm looking to fix by adding some cooling margin to accomodate aftermarket AC without adding full time engine fan load or noise. While the car didn't boil over - it only cooled down in the hotel parking lot with the hood up.  The engine cannot be un-rebuilt and its unclear why its running hotter at idle.  Mixture and timing are good btw.  Running on the highway it was just above the N which is about 190 and my estimate was 85-90 deg in Allentown.

 

Back to the test - about six and a half minutes of running the engine at 1000-1300 rpm, with the clutch engaged got the temp down to 200-205 range then the fan started to cycle off.  This was a big improvement over the stock fan after a heat soak

 

The fans cycling was evidenced by alot of hot air coming out from underneath the car when the fan was on.  It came back on around 205-210.  The infrared thermometer didn't always read the same temperature twice, but you get the idea.  Made sure the hood was up only long enough to take a measurement then put it back down.

 

 

The fan stayed engaged for anywhere between 50 and 90 seconds, stayed off for about 45 seconds.  The gauge movement was pretty imperceptable.

 

Took the car on the open road, 75 deg day, 45 mph for about a quarter mile and it was at 170, fan off.  Highway speeds for about 15 minutes, same result. 

 

 

Back in the garage after the drive, parked close to the wall, waited until air in front of the car was about 90, started the timer but this time idling in Neutral at 650 rpm.. After 25 min, checked the temp at about 190-200 deg.  Fan cycling on for about 5-10 sec, off for about 1 min.  Note when the fan is off it is still moving air.  The car stabilized at this temp.

 

 

Doing some research on Heavy and Severe Duty clutches and fans with a heftier 3 inch pitch.  It seems like the cooling system is just "good enough" right now.  My thought process is if the car can be made to not overheat idling in Drive that may make enough of a representative improvement to handle the AC in N or short periods in D without having to over-rev it.  On the road the worst that could happen is it stabilizes over 200 with the AC on and the fan just periodically roars, but not many other options there.

 

Tim - those temp stickers look familiar - like something that used to be on the side of some big blue test equipment cabinets....   I'm ready to stick them on my head.  Maybe its easier to just roll the window down.

 

 

 

 

 

Edited September 13, 2016 by KAD36 (see edit history)

[avgwarhawk]

Quote

Doing some research on Heavy and Severe Duty clutches and fans with a heftier 3 inch pitch.  It seems like the cooling system is just "good enough" right now.  My thought process is if the car can be made to not overheat idling in Drive that may make enough of a representative improvement to handle the AC in N or short periods in D without having to over-rev it.  On the road the worst that could happen is it stabilizes over 200 with the AC on and the fan just periodically roars, but not many other options there.

 

Yes, the cooling system is good enough for now as the fan clutch with 50% rotating speed of the shaft can only achieve "just good enough".    The heavy duty will be close to 80-90% shaft speed and with a deeper pitch to move more air we could logically conclude this set up will work far better in my opinion.   

[Beemon]

For those interested:

Heavy Duty: #TEM 271303

Severe Duty: #TEM 271301

 

Those are NAPA numbers, price difference is $10 for increased thermal surface area.

 

I can't find any standard clockwise over the counter fan blades, just serpentine blades. Might be an aftermarket/junkyard find. I was surprised, even my local Autozone, whom is filled with cheap go fast trinkets, doesn't have "race performance" clutch fans or flex fans.

 

I was doing some research and it dawned on me that most cars have external coolers for everything - transmission, oil, power steering.... Maybe consideration of a remote oil cooler to dissipate some of that cast iron block heat? Would also theoretically improve the longevity of the oil.

Edited September 13, 2016 by Beemon (see edit history)

[EmTee]

Here's what "Vintage Air" has to say about prepping for the addition of A/C:

 

TIPS:

-Seal and insulate cabin area (including cowl and above evaporator).

-Make sure cooling system and radiator is sufficient.

TIPS:

-Seal and insulate cabin area (including cowl and above evaporator).

-Make sure cooling system and radiator is sufficient.

*Remember, without adequate airflow, a radiator is just a reservoir for hot water. In general,

coolant transfers heat to radiator tubes, tubes transfer heat to fins, and movement of air through

the fins removes heat from the radiator

.You must allow air to pass efficiently through the radiator and out!

*Allow for air to escape from under hood.

*On Walker Radiator or aftermarket: 15-18 lb. Cap.

each 1 lbs. of increased pressure raises boiling point 3° F,

*On original re-core radiator: 4-7 lb. Cap (tanks not designed to hold pressure).

Remember:

Anti-freeze increases boiling point of water (now called anti-freeze/coolant) - proper

mix (50% coolant to 50% water). Corrosion inhibitors protect against scaling and mineral build-up

that can reduce heat transfer. Also, proper maintenance (flushing & changing coolant) will extend

life of system. Use distilled water or pre-mix anti freeze.

-If using an engine driven fan use a shroud.

An unshrouded fan only moves air through the portion of the radiator equal to the surface of the fan.A

shroud also dramatically improves the efficiency of the fan and does not benefit from the housing effect the shroud provides.

An unshrouded fan moves about 50% the volume of a shrouded fan.

*Fan should be ½ to⅔ inside shroud for best performance.

-Water pumps should be overdriven 30 – 35%. (Pulley ratio - crankshaft pulley should be 30%larger than water pump pulley.)

-Always use a thermostat to control engine temperature.

 

Link to the whole document: http://www.vintageair.com/AC Basics/AC BASICS 6 29 09.pdf

[KAD36]

Not to bring up the dreaded clutch fan on a 55 thread again, but......well.....bringing up the dreaded clutch fan on a 55 thread again, thought it would be worthwhile to post final results from this summers work to document results (yeah have some catching up to do!)

 

When I replaced the factory radiator about 15 years ago with a new one (it was the old cellular looking rows, not the serpentine, and kept the original tanks), unbeknownst to me there was a standard and HD core and the standard core (3 row, 9/16 inch centers) is what went in the car.  Wanting to add AC to the car (successfully that is), and not having enough cooling reserve to handle the anticipated condenser heat load, bit the bullet this past summer and went with a HD radiator core, 3 row on 3/8 in centers.  If memory serves I think that came to about 17 more rows over the standard radiator - dont quote me on that. 

 

Difference below, HD on left, standard from the car on the right:

 

After some metalwork and paint on the top tank (fixed the spot on the right after it was in the car):

 

 

Then measured what the absolute largest 6 blade fan that would fit in the shroud opening, which came out to a little over 19.5 inches.  Shifting the shroud down about 1/4 centered it perfectly with the water pump. 

 

If you choose to go with a 6 blade clutch fan vs fixed non clutch setup (the factory set up), here is the Derale fan that was installed with a standard duty clutch:

 

 

Used this setup with the new AC installed and while there were not many days in 90s this past summer in Binghamton, am happy to report that this setup effectively cooled the car down to about 200 with the AC on.  It would not peg at H when left to sit idling in drive in the sun, and when in neutral and revved at fast idle the temp gauge visibly dropped with the fan on.  Additionally I added a 13 lb radiator cap, although for all prior testing a 7 lb cap was adequate to hold pressure even with the needle pegged at hot.

 

In hindsight, probably should have had the HD sized radiator in there all along for a 322.  Expect that would work fine for a non AC car and a 4 blade fan.

 

After putting AC in the car, the idle was bumped up from 475 D to about 550 D, 650 N.  In N with the clutch disengaged and fan spinning it would still pull enough air to hold a rag against the AC condenser.  If I put it on the high speed idle step with the hood closed it held a rag to the grill.  Had no temp issues all summer.  My estimate is the car ran between 185 and 210 with AC on in all kinds of weather and terrain - brief excursion to about 215-220 if coming off a long highway run on a low 90s day and then sitting at a dead standstill on an exit ramp in traffic at idle.  Revving the engine in Neutral slowly brought it back down to the high edge of the N on the temp gauge, or about 190-195.  Naturally the electric fuel pump was on or none of this was possible.

 

Hope this info helps folks.  I have a couple extra fans if anyone is interested - came as surplus in an order.

 

 

 

 

 

 

Edited November 22, 2017 by KAD36 (see edit history)